Obscured by Clouds. The rough and ready blog of a cloud benighted biologist and amateur astronomer. Astroblog will cover my interests in astronomy, biology and Life, the Universe and Everything.

Sunday, December 15, 2013

V1369 Nova Centauri 2013, 12th 13th brightest Nova since 1891

V1369 Nova Centauri 2013 just above beta Centauri at 4:05 am ACDST 15 December (17:35 Dec 14 UT). Stack of 10 images taken using a Canon IXUS, ASA 400, 10 second each exposure. Images registered and stacked with DeepSkyStacker, the converted to RGB and contrast adjusted in ImageJ. Click to embiggen (WARNING, very big file, around 40 Mb)

Labelled expanded image taken using the Canon IXUS, ASA 400, 15 second exposure, 3x Zoom. Central portion of the image to the left, with magnitude comparison stars and the nova indicated. Click to embiggen.

While watching this mornings Geminid meteor shower I got to see V1369 nova Centauri 2013 at a decent height above the horizon, making it easier to estimate the magnitude of the lovely nova.

Note I said "easier", not easy. Even at 4 am the nova is still close to the horizon with significant atmospheric extinction (see top left image).

By unaided eye it looked to be about the brightness of Beta Muscae (magnitude 3.54). When you factor in atmospheric extinction this means its real magnitude is on the order of 3.4.

I also measured the intensities of the star on my photographic images (refernce stars Epsilon Cent, 2.3, Eta Crucis, 3.58, Beta Musc 3.54, Alpha Cricinus, 3.16 and Lambda Cent, 3.1) and did a linear regression. This gave a magnitude of 3.2 for the nova. This is a bit on the high side (star brightness on digital images do not always reflect their V magnitude), but makes me confident my estimate of 3.4 is in the right ball park.

This is consistent with other observers who found that the nova was around magnitude 3.4 at this time, coming down from a peak of 3.3 at 0 UT.

This makes V1369 Nova Centauri the brightest nova since 1999 (V382 Velorum, M2.6), and the 12th 13th brightest nova since 1891! (turns out there is a recuurent Nova that I missed)A good article on nova Centauri 2013 is here.

Date

Nova

Magnitude

1918

V603 Aquilae

-1.4

1901

GK Persei

0.2

1942

CP Puppis

0.3

1925

RR Pictoris

1.2

1934

DQ Herculis

1.4

1975

V1500 Cygni

1.7

1920

V476 Cygni

2

1936

CP Lacertae

2.1

1999

V382 Velorum

2.6

1960

V446 Herculis

2.8

1946

T Coronae Borealis

3

1963

V533 Herculis

3

1912

DN Geminorum

3.5

This means that Nova Centauri 2013 will be visibel to the unaided eye for some time yet, go have a look!